In various industrial applications a fluid is applied to a substrate. One example from the semiconductor industry is the application of glue to a semiconductor wafer, for example, a silicon wafer, for mounting the same to a carrier like a glass carrier prior to carrying out a thinning process like a grinding or etching process.
In such processes, a thinning of the wafer has to be performed as uniform as possible, i.e., a total thickness variation (TTV) of the wafer after the thinning is kept at a minimum, for example, within a limit of ±3 μm. An uneven application of the glue may contribute to the total thickness variation.
Other fluids which may be applied to substrates in industrial processes include imides, lacquers or photoresists. Also, in such cases, a uniform application of the fluid on the substrate, for example, with a thickness variation within desired limits, may be desirable.
In the following, embodiments will be described with reference to the attached drawings. These embodiments serve only as implementation examples and are not to be construed as limiting. For example, other embodiments may include less features, more features, alternative features etc. compared to the embodiments described and shown in the drawings. Moreover, features from different embodiments may be combined with each other unless noted otherwise to form further embodiments.